<template>
  <div class='tizi-carousel' @mouseenter="stop()" @mouseleave="start()">
    <!-- 轮播图图片列表 -->
    <ul class="carousel-body">
      <li class="carousel-item" v-for="(item, i) in sliders" :key="item.id" :class="{ fade: index === i }">
        <RouterLink v-if="item.hrefUrl" :to="item.hrefUrl">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
          <img :src="goods.picture" alt="">
          <p class="name ellipsis">{{goods.name}}</p>
          <p class="price">&yen;{{goods.price}}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <a @click="toggle(+1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
    <!-- 中间的指示器,五个小圆点 -->
    <div class="carousel-indicator">
      <span v-for="i in sliders.length" :key="i" :class="{active: index === i - 1}" @click="index = i - 1"></span>
    </div>
  </div>
</template>
<script>
import {onUnmounted, ref, watch} from 'vue'
export default {
    name:'TiziCarousel',
    props: {
        // 轮播图数据
        sliders: {
            type: Array,
            default: () => []
        },
        // 间隔时长
        duration: {
            type:Number,
            default:3000
        },
        // 是否自动轮播
        autoPlay: {
            type:Boolean,
            default:false
        }
    },
    setup(props) {
        // 默认显示的图片的索引
        const index = ref(0)
        // 自动播放
        let timer = null
        const autoPlayFn = () => {
            // 防止触发多个定时任务
            clearInterval(timer)
            timer = setInterval(() => {
                index.value++
                if (index.value >= props.sliders.length) {
                    // 超过右侧范围,从头开始
                    index.value = 0
                }
            },props.duration)
        }
        watch(() => props.sliders, (newVal) => {
            // 有数据&开启自动播放,才能调用自动播放函数
            if(newVal.length && props.autoPlay) {
              index.value=0
              autoPlayFn()
            }
        }, { immediate:true})
        // 鼠标进入停止,移出开启自动,前提条件: autoPlay 为 true
        const stop = () => {
            if(timer) clearInterval(timer)
        }
        const start = () => {
            if(props.sliders.length && props.autoPlay) {
                autoPlayFn()
            }
        }
        // // 指示器切换上一张下一张
        const toggle = (step) => {
            const newIndex = index.value + step
            if (newIndex >= props.sliders.length) {
                // 超出右侧范围,从头开始
                index.value = 0
                return
            }
            if (newIndex < 0) {
                index.value = props.sliders.length - 1
                return
            }
            index.value = newIndex
        }
        // 销毁组件,清理定时器
        onUnmounted(() => {
            clearInterval(timer)
        })
        return { index, stop, start, toggle}
    }
}
</script>

<style lang="less" scoped>
.tizi-carousel{
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  // z-index: 99;
  .carousel{
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      .slider {
        display: flex;
        justify-content: space-around;
        padding: 0 40px;
        > a {
          width: 240px;
          text-align: center;
          img {
            padding: 20px;
            width: 230px!important;
            height: 230px!important;
          }
          .name {
            font-size: 16px;
            color: #666;
            padding: 0 40px;
          }
          .price {
            font-size: 16px;
            color: @priceColor;
            margin-top: 15px;
          }
        }
      }
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0,0,0,0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background:  #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0,0,0,.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev{
        left: 20px;
      }
      &.next{
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>